[PATCH net-next v3] xfrm: Add ESN support for IPSec HW offload

From: yossefe
Date: Sun Jan 14 2018 - 04:39:40 EST


From: Yossef Efraim <yossefe@xxxxxxxxxxxx>

This patch adds ESN support to IPsec device offload.
Adding new xfrm device operation to synchronize device ESN.

Signed-off-by: Yossef Efraim <yossefe@xxxxxxxxxxxx>
---
Changes from v1:
- Added documentation

Changes from v2:
- Due to Shannon Nelson's request, xfrm_dev_state_add() fails if ESN is
requested and xdo_dev_state_advance_esn() is not implemented
---
Documentation/networking/xfrm_device.txt | 3 +++
include/linux/netdevice.h | 1 +
include/net/xfrm.h | 12 ++++++++++++
net/xfrm/xfrm_device.c | 11 +++++++++--
net/xfrm/xfrm_replay.c | 2 ++
5 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/Documentation/networking/xfrm_device.txt b/Documentation/networking/xfrm_device.txt
index 2d9d588c..50c34ca 100644
--- a/Documentation/networking/xfrm_device.txt
+++ b/Documentation/networking/xfrm_device.txt
@@ -41,6 +41,7 @@ struct xfrmdev_ops {
void (*xdo_dev_state_free) (struct xfrm_state *x);
bool (*xdo_dev_offload_ok) (struct sk_buff *skb,
struct xfrm_state *x);
+ void (*xdo_dev_state_advance_esn) (struct xfrm_state *x);
};

The NIC driver offering ipsec offload will need to implement these
@@ -117,6 +118,8 @@ the stack in xfrm_input().

hand the packet to napi_gro_receive() as usual

+In ESN mode, xdo_dev_state_advance_esn() is called from xfrm_replay_advance_esn().
+Driver will check packet seq number and update HW ESN state machine if needed.

When the SA is removed by the user, the driver's xdo_dev_state_delete()
is asked to disable the offload. Later, xdo_dev_state_free() is called
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 352066e..3c81cd7 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -842,6 +842,7 @@ struct xfrmdev_ops {
void (*xdo_dev_state_free) (struct xfrm_state *x);
bool (*xdo_dev_offload_ok) (struct sk_buff *skb,
struct xfrm_state *x);
+ void (*xdo_dev_state_advance_esn) (struct xfrm_state *x);
};
#endif

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 079ea94..1ca2e6e 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1901,6 +1901,14 @@ int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
struct xfrm_user_offload *xuo);
bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x);

+static inline void xfrm_dev_state_advance_esn(struct xfrm_state *x)
+{
+ struct xfrm_state_offload *xso = &x->xso;
+
+ if (xso->dev && xso->dev->xfrmdev_ops->xdo_dev_state_advance_esn)
+ xso->dev->xfrmdev_ops->xdo_dev_state_advance_esn(x);
+}
+
static inline bool xfrm_dst_offload_ok(struct dst_entry *dst)
{
struct xfrm_state *x = dst->xfrm;
@@ -1971,6 +1979,10 @@ static inline bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x
return false;
}

+static inline void xfrm_dev_state_advance_esn(struct xfrm_state *x)
+{
+}
+
static inline bool xfrm_dst_offload_ok(struct dst_entry *dst)
{
return false;
diff --git a/net/xfrm/xfrm_device.c b/net/xfrm/xfrm_device.c
index 7598250..93520106 100644
--- a/net/xfrm/xfrm_device.c
+++ b/net/xfrm/xfrm_device.c
@@ -147,8 +147,8 @@ int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
if (!x->type_offload)
return -EINVAL;

- /* We don't yet support UDP encapsulation, TFC padding and ESN. */
- if (x->encap || x->tfcpad || (x->props.flags & XFRM_STATE_ESN))
+ /* We don't yet support UDP encapsulation and TFC padding. */
+ if (x->encap || x->tfcpad)
return -EINVAL;

dev = dev_get_by_index(net, xuo->ifindex);
@@ -178,6 +178,13 @@ int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
return 0;
}

+ if (x->props.flags & XFRM_STATE_ESN &&
+ !dev->xfrmdev_ops->xdo_dev_state_advance_esn) {
+ xso->dev = NULL;
+ dev_put(dev);
+ return -EINVAL;
+ }
+
xso->dev = dev;
xso->num_exthdrs = 1;
xso->flags = xuo->flags;
diff --git a/net/xfrm/xfrm_replay.c b/net/xfrm/xfrm_replay.c
index 0250181..1d38c6a 100644
--- a/net/xfrm/xfrm_replay.c
+++ b/net/xfrm/xfrm_replay.c
@@ -551,6 +551,8 @@ static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
bitnr = replay_esn->replay_window - (diff - pos);
}

+ xfrm_dev_state_advance_esn(x);
+
nr = bitnr >> 5;
bitnr = bitnr & 0x1F;
replay_esn->bmp[nr] |= (1U << bitnr);
--
2.8.1